Main Content

step

System object: comm.GeneralQAMDemodulator
Namespace: comm

Demodulate using arbitrary QAM constellation

Syntax

Y = step(H,X)
Y = step(H,X,VAR)

Description

Note

Starting in R2016b, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

Y = step(H,X) demodulates the input data, X, with the general QAM demodulator System object, H, and returns Y. Input X must be a scalar or a column vector with double or single precision data type. When you set the BitOutput property to true and the DecisionMethod property to 'Log-likelihood ratio' the input data type must be single or double precision. Depending on the BitOutput property value, output Y can be integer or bit valued.

Y = step(H,X,VAR) uses soft decision demodulation and noise variance VAR. This syntax applies when you set the BitOutput property to true, the DecisionMethod property to Approximate log-likelihood ratio or Log-likelihood ratio, and the VarianceSource property to 'Input port'.

Note

obj specifies the System object on which to run this step method.

The object performs an initialization the first time the step method is executed. This initialization locks nontunable properties and input specifications. For more information on changing property values, see System Design in MATLAB Using System Objects.